Method of making a dustless road-surface.



No. 881,035. I PATENTED MAR. 3, 1908.

' B. H. THWAITE.

METHODOP MAKING A DUSTLESSROAD SURFACE.

APPLICATION FILED DBO. 9. 1907.

2 SHEBTSSHEET 1.

No. 881,035. PATENTED MAR. 3, 1908. B. H. THWAITE.

METHOD OF MAKING A DUSTLESS ROAD SURFACE.

APPLIOATION FILED DEC. 9. 1907.

' 2 SHEETS-SHEET 2.

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BENJAMIN H. THWAITE, OF LONDON, ENGLAND.

EETHOD OF MAKING A DUST-LESS ROAD-SURFACE.

Specification of Letters Patent.

Patented March 3, 1908.

Application-filed December 9, 1907. Serial No. 405,730.

To all whom it may con Be it knownthat I, ENJAMIN HOWARTH THWAITE, asubject of the King of Great Britain, residing at London, England, haveinvented a certain new and useful Improved Method of Making aDustlessRoad-Surface, of which the following is a specification. My inventionrelates to a method of securing the efficient surfacing of roadways andalso the binding of the materials constituting roadways by means ofhydrocarbons, such as tar and pitch, and thereby producing a (lustlessroadsurface.

To effect a more perfect and permanent binding of the 'roadwa particles,I reliminarily heat the tar and hquid pitch fluid, upto a temperaturethat will secure the removal of any contained moisture, so,that no steamwill be 'eva orated during-the subsequent heating of t e tar. I feedthis preliminarily heated fluid tar and pitchinto a suitable apparatus,where it' is'raised to a tem erature his tarfluid is, by the effect ofhot air pressure,

forced into the roadway surface in fineand uniformly distributed jets,free from water or steam. Now in order to eflectively secure I cry ofthe roller, or oil lamps,

' WhlCli is made the binding of the materials, constituting. the roadwaysurface, with the heated hydrocarbons, I preliminarily heat the roadwayis applied. I

' I effect the heating of the roadway surface by meansof a road rollerso constructed as to permit the ollow, to be heatedto acomparativelyhigh temperature, say 500- Fah, or even higher. v

The roller may be heated b means of a petroleum spray, or other liqui orsolid comust1b1e agent, introduced through the hollow shaft,'or applieddirectly to the periphcoke cradles, or other heating devices may esuspended from the axle of the roller such heatmg devices havingweighted pendulum rods, so that .they remain vertical during therotation of the roller. roller passes over and in contact withthe roadsurface it heats such roadway surface and evaporates the moisture fromthe surface of the silicious and other constituents forming the roadwaysurface, and thus assists insecuring the binding effect of the heated hdrocarbons, on the constituent par ticles be ore mentioned.

lperiphery of such apparatus,

Now as the heated periphery of the The roller may be passed over theroad surface more than once in order that the desired evaporating effectmay be obtained.

The last passage of the roller is immediately in advance of the s rayingmachine. By the distribution of lsuc water-free compound of tar andpitch (heated to the temperature specified) on to 'the preliminarilyheated roadway surface, I obtain a tenacity ofadherence. The resultis'the consolidation of ,the roadway surface by means of a hydrocarbonenvironment.

- In order to sim lify the apparatus forthe dual heating of t e compoundof pitch and tar, I prefer to divide such apparatus into twocompartments, one of which constitutes the feed compartment, which is anopen vessel, and into which the tar and pitch can be directlyintroduced; the other compartment consisting of a closed and pressuresustaining one, being the, compartment in which the temperature isincreased to the degree defined. The liquid tar and itch. are

pumped from the open vessel into t e closed one, and air is also pumpedtherein'to establish any desired ressure, to assistjn ejecting and sraying t e hot hydrocarbon fluid throng a distributing. perforated pipe.A common flue and furnace serves for heating both compartments of theapparatus. 1

Of course I may. employ the two vessels,

one for feeding preliminarily heated tar and pitch and the other fordistributing such cornlpound on to the roadway.

T e pumps I employ -to feed the liquid hydrocarbons into the feed andinto the distributing vessel or compartments are equipped With a ball tye, of non-return valves; they are driven y sprocket and chain or other,mechanical gearmg from the axle of thefeed and spreading machine 'orapparatus.

' may utilize two independent air and hot tar pumpsdriven as described,or I may employ one pump only, so arranged as to pump oth air and fluid,pitch and tar, into the closed and pressurecompartment.

In order to secure the effective spraying of the liquid tar and pitch,by the compressed alr, oriother vapor or gases, stored m the space overthe liquid hydrocarbons,

and wwhich space is connected by valvular connections to the distributintail pi e, I employ acone shaped nozzle, y who the air aspires or drainsand mixes with the'fluid hydrocarbons before the latter enter suchdistributing tribute d thro way surface.

When it is desired to make a temporary application of. my system, Iemploy a tar or pitch and tar feed only, into which I introduce a smallroportion of water to aid the spraying qua ities of the compressed air.Such admixture of water with the tar makes the system independent of theuse ofthe air pumps for tem orary or special purposes where the comp etedehydration of the tar is not essential.

Referring to the drawings accompanying and forming part of thisspecification Figure 1 shows the spray distributing end-view of theanti-dust machine, Fig. 2 is the fire door end-view showing the tarpressure pump, andFig. 3 represents a side elevation of the apparatusshowing the two tar containers. Fig. 4 represents the end view of theheating road roller, and Fig. 5 is a section thereof. Fig. 6 illustratesin section the distributing pipes.

. A is the tar feed container, into whichthe tar is fed through the lidor door A and thence is pumped through a filter box C (shown in dottedlines) by means of the gump D, and delivered into the container underpressure through the connecting pipe F. r i

The tar.in both containers A and E is heated by means of a furnace flueG having an internal, or it may be external firegrate H. The chimney Iserves to take away the products of combustion. V

The hot tar is supplied to the tar spray dispiple, .by. which they aredisug perforations on to the roadtributing pipe hereinafter describedthrou hthe valve equipped outlet J. The high y heated tar is sprayed byair pressure supplied by one or both of the pum s D and D, this pressureof air being app ied to the space over the tar and serves to eject thehighly heated tar through the valve equi ped outlet J and throughtheperforations o the distribution pipe K. When it is desired to furtherspray the heated tar, the air under-pressure iscaused to flow from thecontainer B by means of pipes L from which it flows through the tarspray distributing rear pipe K effectively spraying the hot tar is itleaves the nozzles or perforationsof such pipe K.

1 shows the tar spray distributing pipe K more clearly, as well as thetar flow valvular outlet connections and the air pipes L.

Fig. 2 shows the air and tar pumps D and D, the-pumps being actuated bythe sprocket I rear wheels P.

wheels M, driven, by link chain, orother gear from a sprocket wheeli-N-on the axle O of the A valve equipped connection Q in Fig. 2 permitsmetallic tu'bing'to be rapidly coupled, thus allowing the tar from anordinary dustless road surfaces which consists in ing a highly heatedbody over the roa surface to dehydrate and heat the same, and

equipped with a coke-fire basket 2 or other equivalent fire orburneiy-such as that produced by petroleum oil. This fire-basket 2 iskept in vertical position, more or less perfect by means of the pendulumor hanging or suspended weight 8, the whole being carried by movable orloose collars 4 on the central axis or s indle 5.

he the or flame supplied in the basket 2 of perforated plate iron heatsthe heavy rim 6 of the road'roller and the rim in its rotation transfersthe heat on to the road surface, r'..pidly-evaporating the moisture fromthe road surface, and from immediately beneath it, before the heatedspray is applied. The appara tus is dragged in front of the tar spraymachine above described. Fig. 6 is an enlarged section of Va lveequipped outlet J Fig. 1, but slightly modified as to position of'tarvalve.

The highly heated tar escapes from the heated tar container B, throughthe valve 7., Fig. 6 and air under pressure from the pipe L meets thetar in the valvular-chamber J at the ;mouth of the cone shaped nozzle 8by which the spreading action of the tar is increased throu h the asirator influence of dustless road surfaces consisting in artificiallyheating the road surface and immeditoprovide a covering.

2. The herein described method of making dustless road surfaces whichconsists in dehydrating the road surface by the application ofartificial heat directly thereto and immediately spraying the surfacethus treated with a heated liquid hydrocarbon. g t

3. The herein described method of making assimmediately spraying heatedhydrocarbon thereon before appreciable cooling of said surface.

4. The hereindescribed method of making dustless road surfaces whichconsists in artificially heating the road surface to dehydrate .100ately spraying heated hydrocarbon thereon the same and to ,eflect athorough binding thereof, and spraying heated hydrocarbon on the surfacethus treated toprovide a waterproof wearing surface. v

In testimony whereof I have hereuntoset my hand in presence of twosubscribing witnesse-s; f

. p B. H. THWAITEI Witnesses:

' GEO. HARRISON,

ALEXANDER W. ALLEN.

